Method for the heating of melting furnaces or the like



Patented Jan. 1, 1924.

EDUARD WEYMANN, F DORTMUND, GERMANY. ASSIGITQR TO EISEN-UND STOHLWERKHOESCH AKTIENGESELLSCHAFT, OF DORTMUND, GERMANY.

METHOD FOR THE HEATING OF MELTING FURNACES OR THE LIKE.

No Drawing.

To all whom it may concern:

Be it known that I, Ent'xnn V1-1Y)L\NN,' a citizen of the GermanRepublic. residing at Dortmund. Germany. lrinz Friedrich 5 Karlstrasse35, have invented certain new and useful Improvements in a Method for.

peratures are only obtained by utilizing the hot waste gases inrccnperative chambers for preheating air or gas and air. The waste gasesleave the recuperation chambers at a temperature of 900 to 1100 deg. F.Should this heat. still be used for producing steam, the producedquantity of steam is relatively small.

This heating process thus gives a determined energy circulation which isuneconomic owing to the loss in the recuperative chambers, thedisadvantageous heat exchange and the costs for maintaining the wholerecuperative device.

The present invention now permits more usefully the heating of meltingfurnaces or the like by providing a new and advantage ousenergy-circulation. This energy-circulation is obtained by using oxygengas in combination with combustible gases and Application filed March 1.1923. Serial No. 622,211.

Should the same furnace be worked without preheating air and gas, thereare re tpnred 'per hour about 2-1700 cubic feet of pure oxygen to enrichthe combustion air. llvidently the gas consumption is higher Ill thelatter case owing to the heat recuperated by preheating the air in theother case. The gas consumption increases from 106000 to 124000 cubicfeet per hour.

By utilizing the waste heat of the Martin furnaces in the boilersusually arranged behind the preheating chambers and the change valve,from the 100000 cubic feet of gas will be got 1700 pounds of steam of140 lbs. per so inch superheated to 570 degr. F.

When the combustion air is enriched with oxygen, andsteam is produceddirectly behind the 'l'urnaces (no preheating chambers are provided),from 121000 cubic feet per hour are obtained: 19700 pounds of steam ofH2 lbs. per square inch superheated to 570 degr. F.

From the 18000 cubic feet of gas added per hour there may be produced bydirectly heating'boilers: 5000 pounds of steam.

Consequently, from \Vhcn from this quantity is deducted the quantity ofsteam which can be produced in a boiler provided behind the recuperative,rhamhers, there remains 1t7004i'00:10000 ing liquid air and separatingthe oxygen as,

for instance. the Claud process, requires 0031 ll. l. per cubic foot ofoxygen. In a utilizing the full caloric etlect ot' theSt'lll""ltl()tltl'1t steam turbine plant 0.92 pounds of highly heatedwaste gases directly behind the furnace for energy production, thisenergy being sutlicient to produce the required oxygen. Thisconsiderably simplified energy circulation avoids the large loss andincreases the heat cfiiciency. Recuperation chambers become dispensablewith this method which gives the possibility to use pure oxygen forcombustion purposes.

The advantages of the improved proceeding may be more clearly explainedby the following arithmetical example.

I A 100 tons Martin furnace consumes per hour 106000 cubic feet of cokeoven gas hav ing a calorific value of 025 B. t. u. per cubic foot.

steam of 140 pounds per sq. inch, superheated to 470 deg. F. areconsumed for 1 H. l ./hour.

Consctpicntly, for producing the 24700 cubicfeet of pure oxygen to beadded, a. quantity of 2-t700 0.03-t 9.92:8300 pounds of steam required.

As, however, 10000 pounds of steam "are disposable, there results anexcess of 1700 pounds of steam per hour.

This arithmetical example proves, that the improved proceedingconsisting in a m0ditied energy circulation insures a very economicutilization of the heat. Moreover, it; permits of a remarkablysimplified structure of melting furnaces or the like by avoid- 106000cubic feet would remam 197005000:11T00 pounds of steam.

ing the recuperative chambers and the control-valves, and it results ina considerably reduced expense of entertaining the fun 'naces.

It will be understood that the furnaces may be of any desiredconstruction. Oxygen may be introduced into the burners or into theheads of the furnace or into the nozzles or may otherwise be added. Allthe well known supplying systems may be employed either separately ortogether or interchanging as circumstances may require it.

I claim f The hereindescribed cyclic method which consists generatingthe heat in melting furnaces by oxygenated air and fuel, generatingsteam by heating steam boilers by the gases escaping from said furnaces,utilizing EDUARD \VEYMANN.

Witnesses: v

HENRY \V. Niamey, S. Rooo'rnn,

